document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=823156>Question 823156</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A ball is thrown upward from the top of a building 100 feet high with initial speed 20 ft/sec. The ball hits the ground after... </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #495304 by </B><A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><B>TimothyLamb(4379)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=TimothyLamb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=495304\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ---<BR>\n" );
document.write( "equation of ballistic motion:<BR>\n" );
document.write( "h(t) = -1/2gt^2 + v0t + h0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "on planet earth at the surface of the planet:<BR>\n" );
document.write( "h(t) = -16t^2 + v0t + h0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "for this problem:<BR>\n" );
document.write( "h(t) = -16t^2 + 20t + 100 = 0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the above quadratic equation is in standard form, with a=-16, b=20, and c=100<BR>\n" );
document.write( "---<BR>\n" );
document.write( "to solve the quadratic equation, by using the quadratic formula, copy and paste this:<BR>\n" );
document.write( "-16 20 100<BR>\n" );
document.write( "into this solver: https://sooeet.com/math/quadratic-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "this quadratic has two real roots (the x-intercepts), which are:<BR>\n" );
document.write( "t = -1.95194102<BR>\n" );
document.write( "t = 3.20194102<BR>\n" );
document.write( "---<BR>\n" );
document.write( "negative time doesn't make sense for this problem, so use the positive root<BR>\n" );
document.write( "---<BR>\n" );
document.write( "answer:<BR>\n" );
document.write( "the ball hits the ground about 3.2 seconds after being thrown<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve and graph linear equations:<BR>\n" );
document.write( "https://sooeet.com/math/linear-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve quadratic equations, quadratic formula:<BR>\n" );
document.write( "https://sooeet.com/math/quadratic-formula-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve systems of linear equations up to 6-equations 6-variables:<BR>\n" );
document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );